Inflammatory cytokines compromise programmed cell death-1 (PD-1)-mediated T cell suppression in inflammatory arthritis through up-regulation of soluble PD-1.

The programmed cell death 1 (PD-1) receptor plays a major role in regulating T cell activation. Our aim was to determine how inflammation influences PD-1-mediated T cell suppression. Flow cytometry analysis of rheumatoid arthritis (RA) and psoriatic arthritis (PsA) synovial fluid (SF) mononuclear cells showed an increase in the percentage of PD-1+ cells within the CD4+ and CD8+ T cell compartment compared to paired peripheral blood (PB). Upon in-vitro T cell receptor (TCR) stimulation of healthy control (HC) CD4+ T cells in the presence of plate-bound PD-L1fc chimera, significantly decreased proliferation and interferon (IFN)-γ secretion was observed. In contrast, CD4+ T cells from RA and PsA PB and SF appeared resistant to such PD-1-mediated inhibition. Addition of the proinflammatory cytokines tumour necrosis factor (TNF)α, interleukin (IL)-6 and IL-1ß, which were increased in RA and PsA SF compared to osteoarthritis (OA) SF, consistently abrogated PD-1-mediated suppression in HC CD4+ T cell cultures. This effect was reversed by inhibitors of these cytokines. Soluble PD-1 (sPD-1) levels were increased in cell culture supernatants from TNFα and IL-6-stimulated cultures compared to untreated controls, and also in RA and PsA, but not in OA, serum and SF. Functionally, addition of sPD-1fc counteracted PD-1-mediated suppression of HC CD4+ T cells, and increased T cell proliferation in HC CD4+ T cell/monocyte co-cultures. These in-vitro findings indicate that CD4+ T cells from patients with RA and PsA show increased resistance to PD-1-mediated suppression, which may be explained in part by the presence of soluble PD-1 in the inflammatory environment.

Systemic gene transfer of binding immunoglobulin protein (BiP) prevents disease progression in murine collagen-induced arthritis.

Summary Recombinant human binding immunoglobulin protein (BiP) has previously demonstrated anti-inflammatory properties in multiple models of inflammatory arthritis. We investigated whether these immunoregulatory properties could be exploited using gene therapy techniques. A single intraperitoneal injection of lentiviral vector containing the murine BiP (Lenti-mBiP) or green fluorescent protein (Lenti-GFP) transgene was administered in low- or high-dose studies during early arthritis. Disease activity was assessed by visual scoring, histology, serum cytokine and antibody production measured by cell enzyme-linked immunosorbent assay (ELISA) and ELISA, respectively. Lentiviral vector treatment caused significant induction of interferon (IFN)-γ responses regardless of the transgene; however, further specific effects were directly attributable to the BiP transgene. In both studies Lenti-mBiP suppressed clinical arthritis significantly. Histological examination showed that low-dose Lenti-mBiP suppressed inflammatory cell infiltration, cartilage destruction and significantly reduced pathogenic anti-type II collagen (CII) antibodies. Lenti-mBiP treatment caused significant up-regulation of soluble cytotoxic T lymphocyte antigen-4 (sCTLA-4) serum levels and down-regulation of interleukin (IL)-17A production in response to CII cell restimulation. In-vitro studies confirmed that Lenti-mBiP spleen cells could significantly suppress the release of IL-17A from CII primed responder cells following CII restimulation in vitro, and this suppression was associated with increased IL-10 production. Neutralization of CTLA-4 in further co-culture experiments demonstrated inverse regulation of IL-17A production. In conclusion, these data demonstrate proof of principle for the therapeutic potential of systemic lentiviral vector delivery of the BiP transgene leading to immunoregulation of arthritis by induction of soluble CTLA-4 and suppression of IL-17A production.

Defective CD8+CD28+ regulatory T cell suppressor function in rheumatoid arthritis is restored by tumour necrosis factor inhibitor therapy.

Balanced immunoregulatory networks are essential for maintenance of systemic tolerance. Disturbances in the homeostatic equilibrium between inflammatory mediators, immune regulators and immune effector cells are implicated directly in the pathogenesis of autoimmune diseases, including rheumatoid arthritis (RA). In this study we characterize the peripheral blood CD8(+) CD28(-) regulatory T cells (Treg) contribution to the immunoregulatory network in health and in RA. In health, CD8(+) CD28(-) Treg are suppressive but, unlike CD4(+) Treg , they function predominantly through the action of soluble mediators such as interleukin (IL)-10 and transforming growth factor (TGF)-ß. Neutralization of TGF-ß consistently reduced CD8(+) CD28(-) Treg suppressor function in vitro. RA, CD8(+) CD28(-) Treg are increased numerically, but have reduced expression of inducible co-stimulator (ICOS) and programmed death 1 (PD-1) compared to healthy or disease controls. They produce more IL-10 but autologous T cells express less IL-10R. This expression was found to be restored following in-vitro addition of a tumour necrosis factor inhibitor (TNFi). Deficiencies in both the CD8(+) CD28(-) Treg population and reduced sensitivity of the T responder cells impact upon their regulatory function in RA. TNFi therapy partially restores CD8(+) CD28(-) Treg ability in vivo and in vitro, despite the defects in expression of functionally relevant molecules by RA CD8(+) CD28(-) Treg compared to healthy controls. This study places CD8(+) CD28(-) Treg cells in the scheme of immune regulation alongside CD4(+) Treg cells, and highlights the importance of understanding impaired responsiveness to regulation that is common to these suppressor subsets and their restored function in response to TNFi therapy.

Resolution-associated molecular patterns (RAMP): RAMParts defending immunological homeostasis?

The resolution of inflammation is central to the maintenance of good health and immune homeostasis. Recently, several intracellular stress proteins have been described as having extracellular properties that are anti-inflammatory or favour the resolution of inflammation. We propose that these molecules should be defined as resolution-associated molecular patterns (RAMPs). RAMPs are released at times of cellular stress and help to counterbalance the inflammatory effects of pathogen-associated (PAMPs) and damage-associated (DAMPs) molecular patterns. We propose that heat shock protein 10 (HSP10), αB-crystallin (αBC), HSP27 and binding immunoglobulin protein (BiP) should be considered founding members of the RAMP family. A greater understanding of RAMP biology may herald the development of novel immunotherapies.

BiP regulates autoimmune inflammation and tissue damage.

The endoplasmic reticulum chaperone BiP, in addition to its many important intracellular functions, has anti-inflammatory and immunomodulatory properties when present in the extracellular environment by the stimulation of an anti-inflammatory gene programme from human monocytes and by the development of T-cells that secrete regulatory cytokines such as interleukin-10 and interleukin-4. It can both prevent as well as treat ongoing collagen-induced arthritis. It is, therefore, a potential new biologic therapy for rheumatoid arthritis.

Antibody response to the human stress protein BiP in rheumatoid arthritis.

OBJECTIVES: The human stress protein BiP (immunoglobulin binding protein) has been implicated in the pathogenesis of rheumatoid arthritis (RA) since BiP was found to stimulate synovial T-cell proliferation and anti-BiP antibodies are present in the serum of RA patients. The aim of this study was the development of a rapid and reproducible enzyme-linked immunosorbent assay (ELISA) to determine the specificity and sensitivity of anti-BiP antibodies in RA. METHODS: An ELISA was developed that detected antibodies to BiP. The prevalence of anti-BiP antibodies was determined in sera from patients with early and established RA, sera antedating the onset of RA and sera from patients with other inflammatory and autoimmune diseases and healthy controls. RESULTS: We have confirmed the increased prevalence of antibodies to BiP in the sera of a large cohort of patients with established RA (specificity 71% and sensitivity 73%) and early RA (specificity 65% and sensitivity 66%). In pre-disease sera, median 2.5 yr (interquartile range 1.1-4.7) before symptoms of joint disease, the sensitivity for anti-BiP antibodies was 45% and the specificity was 65% for the development of RA. CONCLUSION: Antibodies to BiP are found in the sera of patients with RA and in sera antedating the onset of RA.

BiP, a putative autoantigen in rheumatoid arthritis, stimulates IL-10-producing CD8-positive T cells from normal individuals.

OBJECTIVES: We have reported that synovial fluid T cells from patients with rheumatoid arthritis (RA) proliferate in response to the endoplasmic reticulum molecular chaperone immunoglobulin binding protein (BiP). The aim of the present work was to clone and define T cells responding to this protein. METHODS: T-cell clones were generated from the peripheral blood of an individual known to respond to BiP by limiting dilution of BiP-stimulated peripheral blood mononuclear cells. T-cell receptor usage of BiP-responsive clones was determined by monoclonal antibody staining followed by flow cytometric analysis. Cytokine production by the BiP-responsive clones was determined by analysis of post-stimulation supernatants by ELISA. Additional phenotyping was performed by flow cytometry. RESULTS: Of 49 clones isolated, six were shown to proliferate in response to BiP. Proliferation was low but consistent. One clone expressed CD4 and five were CD8-positive. Three clones, all CD8(+), grew strongly and were investigated further. T-cell receptor usage was determined in two clones (Vbeta 7.1 and Vbeta 12); the Vbeta element of the remaining clone was not recognized by the panel of antibodies used. All three clones produced interleukin 10 (IL-10) (80-380 pg/ml) and two of them produced IL-4 (10-80 pg/ml) and IL-5 (>5000 pg/ml). One clone produced both IL-10 and interferon gamma (>5000 pg/ml). Additional phenotyping of these clones showed them to express CD25, CD28, CD80 and 86 but not CD56 or 57. One clone constitutively expressed CTLA-4 cytoplasmically. CONCLUSIONS: This study demonstrates that a population of CD8(+) T cells with the cytokine profile of Tc2 cells can be stimulated by the chaperone BiP. These cells may perform a regulatory role in the normal response to inflammation. The increase in response to this antigen in the synovial joint in RA may indicate an attempt to regulate the ongoing inflammation.

The glucocorticoid inhibition of LFA-1 and CD2 expression by human mononuclear cells is reversed by IL-2, IL-7 and IL-15.

Glucocorticoids are agents endowed with powerful immunosuppressive and anti-inflammatory properties partially related to the inhibition of adhesion-related processes. We have previously demonstrated that glucocorticoids inhibit LFA-1 and CD2 expression in human peripheral blood mononuclear cells (PBMC) by down-regulating mRNA steady-state levels. In this study, we investigated whether glucocorticoids could also act indirectly by modulating the effect/function of cytokines whose expression are known to inhibit. To test this hypothesis, we replenished the following cytokines IL-2, IL-7, IL-15, TNF-alpha, IL-1beta, IL-4 and IL-10, in an in vitro PBMC culture system. Our results indicate that only the IL-2Rgamma-chain-dependent cytokines IL-2, IL-7 and IL-15, among the cytokines of this panel, could reverse the inhibition of glucocorticoids on PBMC adhesion molecule expression and the related functions of intercellular aggregation and proliferation. Furthermore, we also demonstrated that IL-2, IL-7 and IL-15 could induce de novo the synthesis of LFA-1 and CD2. Taken together, these data suggest that glucocorticoids inhibit PBMC LFA-1 and CD2 expression not only directly by modulating transcriptional events, but also indirectly through the inhibition of IL-2Rgamma-dependent cytokines.

Pathogenesis of rheumatoid arthritis. The role of T cells and other beasts.

The evidence coming from the different experimental approaches reviewed in this article strongly supports the hypothesis that RA is T-cell driven at all stages of the disease. Although the effector phases responsible for the events that lead to joint destruction involve several different cell types, cytokines, and other mediators, T cells still direct operations behind the scenes. Direct experimental proof of this proposition in patients is still lacking, but the development of nondepleting modulating CD4 monoclonal antibodies may provide new tools to test this hypothesis. In this respect, it is encouraging that using one such reagent, we have recently shown that not only did the activity of the disease improve but, more importantly, the inflammatory indices and production of non-T-cell cytokines were reduced. This is not to dissimilar from the results of experiments described in animals, where by blocking synovial T cells, the production of IL-1 beta and TNF alpha could be decreased by more than 90%. From this perspective, it may be predicted that by modulating T cells in the joint, it is possible to achieve our ultimate goal of permanently switching off the disease.

Functional IL-2 receptor beta (CD122) and gamma (CD132) chains are expressed by fibroblast-like synoviocytes: activation by IL-2 stimulates monocyte chemoattractant protein-1 production.

The expression of the IL-2R alpha-, beta-, and gamma-chains, CD25, CD122, and CD132, respectively, was investigated on fibroblast-like synoviocytes (FLS) and dermal fibroblasts (DF). Both protein and mRNA for CD122 and CD132 were observed but there was no evidence of CD25 expression. Quantification of the Ag binding sites for CD122 showed that FLS expressed 4 times more receptor molecules than DF. The functional capability of these receptors was confirmed by the production of monocyte chemoattractant protein-1 (MCP-1) in direct response to stimulation by IL-2, which could be inhibited by neutralizing anti-CD122 mAb. Both rheumatoid arthritis (RA) and osteoarthritis (OA) FLS and DF spontaneously produced MCP-1 in culture over a similar range of concentrations. However, RA and OA FLS produced significantly greater levels of MCP-1 following stimulation by IL-2 and IL-1 beta; RA FLS produced significantly more MCP-1 than OA FLS. Addition of exogenous IL-2 caused a slight, but significant, decrease in MCP-1 production by DF. The addition of neutralizing anti-CD122 mAb to FLS cultures partially, but significantly, reduced the IL-2-induced MCP-1 secretion, but did not effect either the spontaneous or IL-1 beta-induced secretion of MCP-1. Increased tyrosine phosphorylation was observed in FLS lysates following 30-min incubation with IL-2. In conclusion, in the inflamed synovium, as activated T cells migrate through the sublining and lining layer, T cell-derived IL-2 may activate FLS to secrete MCP-1, thus recruiting macrophages into the rheumatoid synovium and perpetuating inflammation.

The human endoplasmic reticulum molecular chaperone BiP is an autoantigen for rheumatoid arthritis and prevents the induction of experimental arthritis.

Rheumatoid arthritis (RA) is the most common, crippling human autoimmune disease. Using Western blotting and tandem mass spectroscopy, we have identified the endoplasmic reticulum chaperone BiP, a 78-kDa glucose-regulated protein, as a possible autoantigen. It preferentially stimulated increased proliferation of synovial T cells from patients with RA but not from patients with other arthritides. Mice with established collagen- or pristane-induced arthritis developed IgG Abs to BiP. Although BiP injected in CFA failed to induce arthritis in several strains of rats and mice, including HLA-DR4(+/-)- and HLA-DR1(+/+)-transgenic animals, it completely inhibited the development of arthritis when given i.v. 1 wk before the injection of type II collagen arthritis. Preimmunization with BiP suppressed the development of adjuvant arthritis in Lewis rats in a similar manner. This is the first report of a mammalian chaperone that is an autoantigen in human RA and in experimental arthritis and that can also prevent the induction of experimental arthritis. These findings may stimulate the development of new immunotherapies for the treatment of RA.

Lack of CD80 expression by fibroblast-like synoviocytes leading to anergy in T lymphocytes.

OBJECTIVE: To investigate whether contact with HLA-DR+, but CD80-, fibroblast-like synoviocytes (FLS) in the presence of antigen leads to the induction of anergy in, rather than stimulation of, T cells. METHODS: Cell surface expression of activation and costimulatory markers on FLS were studied by flow cytometry. Functional changes were investigated by T cell proliferation to tuberculin purified protein derivative or allogeneic responses to FLS, in the presence or absence of DAP3.B7 cells, a human CD80-transfected mouse fibroblast cell line. Induction of anergy was investigated by a 2-stage culture system. T cells were cocultured with allogeneic FLS in the primary culture, rested, and restimulated in the secondary culture by FLS in the presence or absence of DAP3.B7 cells or interleukin-2 (IL-2). RESULTS: Direct contact between T cells and FLS caused up-regulation of CD69 on T cells and HLA-DR on FLS in both the allogeneic and autologous cultures. The addition of DAP3.B7 cells to FLS-T cell cocultures restored the depressed allogeneic responses of T cells. The allogeneic response by T cells to FLS in the presence of DAP3.B7 cells could be completely inhibited by blocking CD80 with CTLA-4 Ig. Indirect evidence that T cells cocultured with FLS were anergic was the up-regulation of CD25, negligible T cell proliferation, and the restoration of proliferation by the addition of exogenous IL-2. Direct evidence of anergy was obtained when T cells from the primary cultures with FLS remained unresponsive to secondary culture with FLS even in the presence of DAP3.B7 cells. In contrast, primary culture of T cells with FLS plus DAP3.B7 cells initiated a good allogeneic response in all subsequent cultures. CONCLUSION: It is possible that T cells within the synovium may be anergized by contact with HLA-DR+ CD80- FLS.

The relative proportions of secreted interleukin-2 and interleukin-10 determine the magnitude of rheumatoid arthritis T-cell proliferation to the recall antigen tuberculin purified protein derivative.

OBJECTIVE: To investigate the mechanisms of the deficient proliferative responses by rheumatoid arthritis (RA) peripheral blood T cells to the recall antigen tuberculin purified protein derivative (PPD). METHODS: The concomitant production of interleukin (IL)-2, IL-10 and lymphocyte proliferation were studied by enzyme-linked immunosorbent assay and [(3)H]thymidine uptake, respectively, in 12 normal controls and eight RA patients. RESULTS: An inverse correlation was found between IL-10 production and proliferation to PPD. The proliferative response was shown to be critically affected by the IL-2:IL-10 ratio so that absolute levels of secreted IL-2 or IL-10 correlated non-significantly with lymphocyte proliferation. CONCLUSION: The deficient T-cell proliferation in RA peripheral blood mononuclear cells is related to the relative proportions of IL-2:IL-10 rather than the absolute amounts secreted.

The sequential analysis of T lymphocyte subsets and interleukin-6 in polymyalgia rheumatica patients as predictors of disease remission and steroid withdrawal.

CD4 and CD8 T lymphocyte subsets, the late T cell activation marker, HLA-DR, and serum interleukin-6 (IL-6) levels of 57 polymyalgia rheumatica (PMR) patients were followed over 2 yr to investigate whether they could be used to predict the safe withdrawal of steroid therapy. Cell phenotypes were studied by flow cytometry and IL-6 levels by ELISA. %CD8 cells were reduced below the normal range in PMR patients prior to steroid therapy. In 56% of patients, the %CD8 T lymphocytes failed to return to normal levels when quiescent disease allowed cessation of steroid therapy. Activated CD8 T cells, as detected by HLA-DR positivity, were above the normal range at the initiation of therapy and showed a negative correlation with %CD8 T cells. The serum concentration of IL-6 fluctuated over 24 months, and the correlation between IL-6 and erythrocyte sedimentation rate (ESR) seen prior to treatment was not seen at later intervals. The %CD8 T cell and serum IL-6 levels are not a good indicator of disease activity in PMR and are, therefore, unable to predict the safe withdrawal of steroids.

Effects of inflammation and treatment on bone turnover and bone mass in polymyalgia rheumatica.

OBJECTIVE: Polymyalgia rheumatica (PMR) has an abrupt onset of inflammatory symptoms, making it a useful model for studying the effects of inflammation in bone. PMR requires corticosteroid treatment, which may itself have a detrimental effect on bone. This study used serially measured biochemical markers of bone turnover and bone density to address the relative contributions of systemic inflammation and corticosteroid therapy to bone loss. METHODS: Fifty untreated patients with PMR were randomized to receive oral prednisolone or intramuscular methylprednisolone. Biochemical bone markers (pyridinoline [PYR], deoxypyridinoline [DPYR], procollagen type I carboxy-terminal peptide [PICP]) and bone mineral density (BMD) were measured at baseline and at 6, 12, and 24 months. RESULTS: The median disease duration at presentation was 12 weeks (range 5-32 weeks). Levels of urinary crosslinks were increased in patients with untreated PMR compared with controls (PYR 74.9 +/- 30.0 nmoles/mmole creatinine, DPYR 14.6 +/- 6.4 nmoles/mmole creatinine [mean +/- SD]; P = 0.0001); the PICP level was normal (115.0 +/- 39.0 microg/liter). With treatment, the crosslinks levels fell and PICP levels rose within 6 months (P = 0.01). Bone resorption (PYR) correlated with untreated disease activity (erythrocyte sedimentation rate [ESR]) (r = 0.5, P = 0.003) and with interleukin-6 levels (r = 0.48, P = 0.05). There was a significant reduction in BMD of both the hip and the spine after 12 months of treatment (P = 0.0002), with no difference between treatment groups. As the steroid dosage was reduced, bone mass improved. Initial ESR influenced the percent change in BMD at 1 year (r = 0.35, P = 0.05), while cumulative steroid dose, mean ESR, and type of steroid used did not. CONCLUSION: Inflammation in PMR increases bone resorption and appears to have a more detrimental effect on bone than does low-dose corticosteroid. If corticosteroids can be tapered and discontinued, bone loss in PMR can be a transient phenomenon.

Large granular lymphocyte expansions in Felty's syndrome have an unusual phenotype of activated CD45RA+ cells.

One-third of patients with Felty's syndrome (FS) have significant clonal expansions of CD3+ CD8+ large granular lymphocytes (LGLs) in their peripheral blood. The reasons for this are unclear, but one hypothesis is that they are activated antigen-specific cells of pathogenic relevance. Cytofluorographic analysis of activation markers demonstrated that the cell surface phenotype of these expansions was CD57+, HLA-DR+, IL-2R-, Leu-8+, CD69+, LFA-1+, ICAM-1+, VLA-4+, i.e. 'activated' T cells. However, they also expressed the phenotype CD45RA+, CD45RBbright, CD45RO-, usually associated with 'naive' cells. This could result from aberrant activation, malignant transformation or from a 'reversal' of CD45 phenotype following chronic antigenic stimulation. In three patients with RA and non-clonal LGL expansions, a more variable phenotype was found. In one of these patients, the expanded population was identified in the peripheral blood, but not the synovial fluid. This may suggest that, at least in this individual, any pathogenic effect is exerted systemically.

T-lymphocyte immunophenotyping in polymyositis and dermatomyositis.

The objective was to elucidate the immunological abnormalities underlying polymyositis (PM) and dermatomyositis (DM). The phenotype of peripheral blood mononuclear cell (PBMNC) subsets and cell surface expression of activation (CD25 and HLA-DR) and adhesion (LFA-1) molecules was studied in 12 patients with PM and in 10 patients with DM. PBMNC subsets and expression of T-cell activation molecules were evaluated by cytofluorography. Double immunofluorescence and indirect immunoperoxidase techniques were applied to muscle biopsies to define T-cell phenotype and LFA-1/ICAM-1 expression. In PM, the absolute number of circulating cytotoxic (CD8+CD28+) T cells was selectively reduced. T cells showed increased expression of activation molecules, CD25 and HLA-DR, and increased adhesion capacity as the absolute numbers of CD3+CD25+, CD8+HLA-DR+, CD3+LFA-1+('bright') and CD8+ CD8+LFA-1+('bright') cells were higher than in healthy donors and DM patients. In PM muscle biopsies, T cells were mainly CD3+CD8+ and LFA-1+; additionally, endothelial cells and myofibres surrounded by T cells showed positive staining for ICAM-1. In DM, there was a general lymphopenia that led to a decreased absolute number of all T-lymphocyte subsets. It is proposed that in PM, in contrast to DM, LFA-1/ICAM-1 interactions enable activated CD8+ T cells to migrate selectively into the inflamed muscle and to adhere to myofibres, leading to tissue injury.

Hematologic and cytofluorographic analysis of patients with Felty's syndrome. A hypothesis that a discrete event leads to large granular lymphocyte expansions in this condition.

OBJECTIVE: To compare hematologic and cytofluorographic features in Felty's syndrome (FS) patients with and without the large granular lymphocyte (LGL) syndrome. METHODS: Peripheral blood cells from FS patients and from 2 control groups (rheumatoid arthritis [RA] patients and subjects without symptoms of a rheumatic disease) were analyzed by hematologic and cytofluorographic techniques. A separate assessment of disease activity was performed. RESULTS: FS patients had reduced lymphocyte and platelet counts, with a parallel reduction in lymphocyte subsets examined. CD4 counts were reduced in all FS patients, including those with the LGL syndrome. Disease activity was lower in FS patients than in RA control patients. Treatment was similar in all patient groups. No direct association was seen between LGL numbers and duration of RA or neutrophil counts in RA groups. CONCLUSION: Hematologic abnormalities in FS extend beyond neutropenia. Although similarities were seen between FS patients and FS patients with the LGL syndrome (e.g., CD4 lymphopenia), evidence for a gradation from FS to the LGL syndrome was not seen, thus favoring the hypothesis that a "transforming event" is required.

Large granular lymphocyte expansions in patients with Felty's syndrome: analysis using anti-T cell receptor V beta-specific monoclonal antibodies.

Felty's syndrome (FS), the association of rheumatoid arthritis (RA) and idiopathic neutropenia, remains an unexplained phenomenon. HLA-DR4 is found in over 90% of cases. Patients with FS may have a T cell lymphocytosis of CD3+CD8+CD57+ large granular lymphocytes (LGL syndrome). In this study of 47 patients with FS, 19% had clear evidence for LGL expansions, while in total 42% had variable evidence for the LGL syndrome using currently available techniques. Of these T cell expansions, 76% were clonal, as demonstrated by Southern blotting and analysis with T cell receptor (TCR) beta chain constant region probes. This technique may fail to detect clonal populations in some patients. Cytofluorographic analysis using antibodies specific for TCR V beta chains identified patients with clonal LGL expansions with results comparable to those obtained with Southern blotting. No evidence for shared V beta usage among expansions from different patients was seen. The role of LGL in RA and FS is currently unclear, but this technique offers a practical and accessible means of identifying patients with LGL expansions, as a starting point for further investigation.

The value of percentage of CD8+ T lymphocyte levels in distinguishing polymyalgia rheumatica from early rheumatoid arthritis.

OBJECTIVE: To determine whether the low absolute numbers and percentages of CD8 positive T cells in the circulation of patients with polymyalgia rheumatica (PMR) could be used as a new diagnostic criterion for the disease. METHODS: The % CD4 and CD8 positive T lymphocyte sub-populations were measured in 37 patients with PRM before treatment and during steroid treatment over the subsequent 2 years, in 21 patients with rheumatoid arthritis (RA), and in 27 normal (N) control subjects. RESULTS: During the study, 10 patients, who were initially diagnosed as PMR, were reclassified as having had a myalgic onset of RA (PMR-RA), according to the American College of Rheumatology criteria for the diagnosis of RA. No decreased %CD8+ T lymphocyte subset had been observed in these patients at presentation, before steroid therapy, or during treatment with steroids when compared with the RA and N groups. CONCLUSION: The measurement of %CD8+ T cell subset may provide a simple method for determining whether patients presenting with myalgia are "true" PMR or are destined to develop RA.